The SSM22111 is a high performance audio amplifier that delivers 1 W RMS of low distortion audio power into a bridge-connected 8 ? speaker load (or 1.5 W rms into a 4 ? load).

The SSM2211 operates over a wide temperature range and is specified for single-supply voltages between 2.7 V and 5.5 V. When operating from batteries, it continues to operate down to 1.75 V. This makes the SSM2211 the best choice for unregulated applications, such as toys and games.

Featuring a 4 MHz bandwidth and distortion below 0.2% THD + N @ 1 W, superior performance is delivered at higher power or lower speaker load impedance than competitive units. Furthermore, when the ambient temperature is at 25?C, THD + N < 1%, and VS = 5 V on a four-layer PCB, the SSM2211 delivers a 1.5 W output.

The low differential dc output voltage results in negligible losses in the speaker winding and makes high value dc blocking capacitors unnecessary. The battery life is extended by using shutdown mode, which typically reduces quiescent current drain to 100 nA.

Download the datasheet document of SSM2211 for 1.5W audio amplifier circuit reference:

SSM2211 Datasheet

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This is the circuit diagram of 24 Watt class A linear audio amplifier, built and tested by Marc Klynhans from South Africa. The supply voltage can be between 34V and 46V and the quiescent current should be set to 1.7A measured through R25 (a voltage of 0.75V must be measured over R25 for a quiescent current of just under 1.7A). R23 is a trimmer and must be set to maximum resistance (10kOhm) when powering up. Then the resistance of R23 must be decreased until the the quiescent current is achieved. If the amplifier is mounted on a big enough heatsink ( 0.6K/W at most) then the amplifier is very safe from thermal runaway. Intelligence must be used when choosing power and voltage ratings of resistors and capacitors.

24W Audio Amplifier (Class A) Specifications:

• 24W Class A into 8 Ohm
• 100mHz – 100kHz flat
• 305mV input for 24W into 8 Ohm (33dB gain)

Schematic Diagram:

Component part list:

PCB Layout:

Component Placement:

Take a note that this amplifier requires dual polarity power supply. Build the power supply using center tap transformer with output current 2A minimum and output voltage 30V, use about 6800 uF – 10000 uF electrolityc capacitors (elco). Good luck.

source: http://users.otenet.gr/~athsam/power_amplifier_35w_with_lm391.htm

Parts list:

Power supply parts:

18W Audio Amplifier Circuit Notes:

• Can be directly connected to CD players, tuners and tape recorders.
• Don’t exceed 23 + 23V supply.
• Q3 and Q4 must be mounted on heatsink.
• D1 must be in thermal contact with Q1.
• Quiescent current (best measured with an Avo-meter in series with Q3 Emitter) is not critical.
• Adjust R3 to read a current between 20 to 30 mA with no input signal.
• To facilitate current setting add R8 (optional).
• A correct grounding is very important to eliminate hum and ground loops. Connect in the same point the ground sides of J1, P1, C2, C3 &C4. Connect C6 at the output ground.
• Then connect separately the input and output grounds at the power supply ground.

Components List:

R1 _____________ 1K
R2 _____________ 1M
R3 _____________ 22K
R4 _____________ 10K
R5 _____________ 180K
R6 _____________ 1R

IC1 ____________ LM1875

C1 _____________ 1uF 50V
C2,6 ___________ 100nF
C3 _____________ 22uF 63V
C4 _____________ 0.22uF
C7,5 ___________ 220uF 50V     

Miscellaneous:
Fuse holder & cover
2 amp fuses

Circuit Description:
The IC can be used with two power supply arrangements single supply and dual supply. We have decided to use the dual supply version. The single supply version would require the use of 63V electrolytic capacitors, thus increasing the cost and overall size of the module.

The input signal is coupled via R1 and C1 to the noninverting input (pin 1) of the IC. The closed loop gain of the amplifier is set to 19 by resistors R5 (180K) and R4 (10K). R4 and C3 (22uF) set the lower 3dB frequency point to 7Hz.

The output appears at pin 4 of the IC and drives a loudspeaker directly. Long speaker leads can produce enough capacitance to drive amplifiers into VHF oscillation. Resistor R6 (1W) and capacitor C4 (0.22uF) help prevent this. They are connected across the output and form a Zobel network which provides high-frequency stability when driving capacitive loads.

The IC power supply is connected via 2A fuses to protect against any external shorts to ground. Capacitors C5 and C7 provide further on-board supply decoupling.

Power Supply
The module is powered by a dual +/- 25V supply. These rails are supplied by a separate power supply board.

We have one kit available for this purpose – Kit 114. It consists of four diodes (1N5401) connected as a bridge rectifier and four electrolytic capacitors (2200uF) to smooth out the ripple.

The mains transformer used to power the module should be rated at 60VA with a 35V centre-tapped secondary winding. A 30V secondary winding transformer could also be used but the lower DC output would result in reduced power output.

If you want to run two modules in a stereo amplifier you can use a common power supply. In this case the transformer should be rated at 80VA

LM1875 Specs:

• Short circuit protection
• 94dB supply rejection ratio
• Up to 30W output power into 8 ohms
• Typical THD of 0.015% @ 1kHz, 20W output
• In-built thermal protection
• S/N ratio in excess of 100dB
• Open loop gain typically 90dB
• 70mA quiescent current (typical)

Download 25W Hi-Fi Audio Amplifier based LM1875 circuit kit manual:
[wpdm_file id=37]
Download LM1875 Datasheet:
[wpdm_file id=38]

The TDA1553CQ is a monolithic integrated class-B output amplifier in a 13-lead plastic DIL-bent-SIL power package. It contains 2×22 W amplifiers in BTL configuration. The device is primarily developed for car radio applications.

The TDA1553CQ contains two identical amplifiers with differential input stages and can be used for bridge applications. The gain of each amplifier is fixed at 26 dB.

Special features of the device are:

3-state mode switch
? standby: low supply current (<100 mA)
? mute: input signal suppressed
? operating: normal on condition.

Loudspeaker protection
When a short-circuit to ground occurs, which forces a DC voltage across the loudspeaker of >= V, a built-in protection circuit becomes active and limits the DC voltage across the loudspeaker to <= V. Pin 12 detects the status of the protection circuit (e.g. for diagnostic purposes).

Short-circuit protection
If any output is short-circuited to ground during the standby mode, it becomes impossible to switch the circuit to the mute or operating condition. In this event the supply current will be limited to a few milliamps.

Download the TDA1553CQ datasheet from below link:
[wpdm_file id=33]

Here the Amplifier Circuit Diagram:

Here the PCB layout:

About LM12:
The LM12 is a power op amp capable of driving +25V at? +10A while operating from +30V supplies. The monolithic? IC can deliver 80W of sine wave power into a 4X load with? 0.01% distortion. Power bandwidth is 60 kHz. Further, a? peak dissipation capability of 800W allows it to handle reactive? loads such as transducers, actuators or small motors? without derating. Important features include:

• Input protection
• Controlled turn on
• Thermal limiting
• Overvoltage shutdown
• Output-current limiting
• Dynamic safe-area protection

Download the LM12 datasheet from below link:
[wpdm_file id=32]

There are possible alternative input stage transistors, the Toshiba 2SA970BL and 2SC2240BL, which appear to be good substitutes for the Hitachi 2SA1085E and 2SC2547E. The ‘BL’ suffix is the high gain group. Alternatives for the Sanyo 2SC2911 and 2SA1209 are the Toshiba 2SC3423 and 2SA1360.

This 70W power amplifier is designed for quality rather than quantity, and if much higher power is really needed there are other more suitable design approaches.

This is an awesome amplifier circuit, and this is the older version?(MJR7-Mk3). There is new version released (MJR7-Mk5) for better quality and performance, just go to THIS PAGE for complete circuit explanation.

Components list:

R1, R3 _________ 1K2 ohm
R2, R4 _________ 18 ohm
R5, R6 _________ 1 ohm
C1, C2 _________ 3u3 50V mini
C3 _____________ 22uF 16V
C5 _____________ 100uF 35V
C6, C7 _________ 220uF 10V
C10, C11 _______ 2200uF 35V
C4, C8, C9 _____ 100nF
IC _____________ TDA2009A
Heat sink

Circuit Specifications :

D.C. Input         : 8 ? 24V at 1 ? 2 A
Power output       : > 10W RMS /channel, 4 ohm load, 24V DC supply.
                     > 6W RMS /channel 8 ohm load 24V DC supply.
                     > 4W RMS /channel, 4 ohm load 12V DC supply.
S/N ratio          : > 75 dBA re. 10W output.
Frequency response : ~ 10 Hz to 50 kHz ?3 dB
Gain               : ~ 36 dB
Input level        : ~ 100 mV for full output

Circuit Works:
C1 & C2 are input coupling capacitors and block DC, as do C10 & C11 which are the output coupling capacitors, and C6 & C7 which block DC from the feed back loop. R1/R2 (and R3/R4) set the level of feed back.

The gain is equal to 1 +(R1/R2) = 68 or 37 dB. C8/R5 (and C9/R6) provide a high frequency load for stability where loudspeaker inductive reactance may become excessive. C4 and C5 provide power supply decoupling or filtering.

Kits:

The kits of this circuit is available at electronickits.com, you can order the kit there with online transaction.

Download 2x10W audio amplifier kit manual include the schematic diagram and the explanation:

10W Stereo Power Amplifier TDA2009A

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Download TDA2009A Datasheet Document:

TDA2009A Datasheet

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Components List:

Resistors :
R1, R2 ___________________ 2R2 ohm

Capacitors :
C1, C2, C4, C5, C6 _______ 100uF/16V electrolytic capacitor
C3 _______________________ 10uF/16V electrolytic capacitor
C7, C8, C12 ______________ 100nF
C9 _______________________ 2,200uF/25V electrolytic capacitor
C10 ______________________ 1uF/50V electrolytic capacitor
C11 ______________________ 100pF

Misc.
I.C. _____________________ HA13118
Heatsink

C10 is the input coupling capacitor and blocks DC from the input. C11 bypasses any RF which may be present at the input. C1 & C2 provide an AC ground for the inverting inputs of the IC. R1/C7 and R2/C8 provide a high frequency load for stability with difficult speakers. C5 and C6 provide “bootstrap” feedback for the IC. C9 and C12 provide power supply filtering. Don’t forget that heatsink is a must for this class AB power amplifier circuit.

18 Watt Audio Amplifier Specifications :

D.C. Input     : 8 ? 18V at 1 - 2 A
Power output   : 18W maximum, 4 ohm load, 18V DC supply
                 > 10W RMS 4 ohm load, 18V DC supply
                 > 5W RMS 8 ohm load 18V DC supply
                 > 6W RMS 4 ohm load 12V DC supply
S/N ratio      : > 70 dB
THD              < 0.2% @ 1W
Freq. Response : ~ 30 Hz to 30 kHz, ?3 dB
Input level    : < 25 mV, for full output (G > 50dB)
Input Impedance  ~ 30 k ohm

Download 18 Watt Audio Amplifier with HA13118 full explanation:

18W Power Audio Amplifier

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Download HA13118 datasheet:

HA13118 Datasheet

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